The objective of this Inter-Agency Agreement is to implement a hearing examination protocol in the Early Childhood Longitudinal Study of the Kindergarten Class of 2010?11. This is a large (n=20,000), nationally representative school-based exam and interview survey sponsored by the National Center for Education Statistics (NCES), U.S. Department of Education. The last NCES longitudinal cohort study of school age children began with the 1998 Kindergarten Class. In this earlier cohort, there were no hearing exams (nor vision exams) and the number of young children with hearing loss (reported by parents or teachers) shrank considerably after the initial enrollment of Kindergarteners. In the U.S., the last comprehensive national study of children with hearing exam measures was the 1963?1965 National Health Examination Survey (NHES, i.e., the predecessor of NHANES) for children aged 6 to 11 years. A randomly selected sub-sample of about 4500 children were identified for more frequent follow-up and these children have also been selected for the hearing examination; they are also included in a ?selected? (protected) subsample for more intensive tracking in follow-up waves of the survey. Children in the selected subsample will be tracked to new schools when possible if they are later enrolled in (moved to) a school that was not in the original school sample, e.g., when families relocate. In addition to hearing, the ECLS-K: 2010-11 will track several other outcome measures (e.g., general health, social and physical development, achievement scores, and parental and teacher-reported communication problems) associated with educational performance. Hearing will be tested when the children are examined with achievement testing in the school setting. NCES has awarded a contract to WESTAT to conduct the field operations, including selection of sample schools, data collection, and preparation of user-friendly research data files. The contractor will obtain longitudinal measures of hearing sensitivity and middle ear function of Kindergartners during the fall of Second grade (calendar year 2012), spring of Third grade (calendar year 2014), and spring of Fifth grade (calendar year 2016). Hearing thresholds will be recorded from each ear separately. In addition, the contractor will obtain tympanometric traces to assess middle ear function and, also, wideband reflectometry beginning in the spring of Third grade to improve classification of sensorineural versus conductive hearing loss.